Oldpuck went into detail how manufacturing processes work going from prototype stage to beta product to mass production etc. Unfortunately I cannot find the post because I don't think I can search his former "deleted member" comment history.
(edit:
Found the post - bookmarked it this time)
If Switch 2 is similar to Switch (rails, tablet design, etc), that would probably help a bit in the planning/design phase.
But I don't think this would help reduce the manufacturing process. It's still different parts, different processes, different screws, etc. They have to do test/practice assembly runs, just like they did for SWOLED and Switch Lite. Gotta find the right amount of efficiency before they can officially begin mass production.